Parasitic battery drain?

Discussion in 'Gen 5 Prius Technical Discussion' started by Paul Gregory, Mar 10, 2024.

  1. Gokhan

    Gokhan Senior Member

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    That's good, and it might help a little as a small Band-aid solution, but the real reason for the battery problems is the charging system (battery-management system with the battery sensor) that minimizes the charging, not the parasitic drain.

    And you shouldn't keep the car plugged in—TSB or not.
     
  2. Stephane28

    Stephane28 New Member

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    Hello, thanks for sharing your experience.

    Can you please provide more detail about the TSB you mentioned above (TSB-TCI-6016 CODE EE2411)? Do you have a link or additional info? I cant find anything about it online.

    The only TSB related to the 12V battery that I could find is the T-SB-0054-24 (see attached).

    Do you think it is related to the TSB you mentioned?

    Thanks
     

    Attached Files:

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  3. Gokhan

    Gokhan Senior Member

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    That seems to be the appropriate TSB, yes.
     
  4. Zeromus

    Zeromus Active Member

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    Fun fact, I took my car in today for its 1 year service, this TSB or one like it, doesn't exist for the Canadian market. Seems to be US market only.

    It could be related to the fact that we have the Alaska/Canada "warming control" mode in our programming, which will let the car keep the battery warm if its plugged in for an extended period of time. If you leave it plugged in for more than 3 days, the battery heater will continue to work to prevent the battery from freezing for up to 31 days while plugged in.

    Relevant text from user manual:
    Hybrid battery (traction battery) warming control (Alaska and Canada only) This control operates after the AC charging cable remains connected to the vehicle for 3 days and “Battery Heater” automatically stops. It automatically insulates the hybrid battery (traction battery) in extremely low temperatures.  This control stops 31 days after the AC charging cable is connected, even if it is still connected to the vehicle.  When this control operates, charging schedule settings are ignored and charging starts.

    I think warming control kicks in before the 3 days though because on particularly cold mornings, even in my (unheated but lightly insulated garage), I get the following message: "The Traction Battery Temp is low System put priority on charging to preserve battery condition” is shown (Alaska and Canada only)". According to the manual this message is shown when it was cold and the car was plugged in, and warming control was operating.

    So its possible that the ECU issue and software fix just don't apply to Canada? Or maybe the Canadian Toyota hasn't updated a TSB yet. I had the 12v die on me a few times this winter, though only once since they fully charged it when I went in for the recall repair in December I think it was.
     
  5. Mendel Leisk

    Mendel Leisk Senior Member

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    I guess Toyota didn’t hear about the northern US prairies.
     
  6. Paul Gregory

    Paul Gregory Active Member

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    Well, I guess I'm screwed. It has been -25C for a few weeks here, and I'm sure my battery was getting a charge during normal operation. I don't have a heated garage, so the battery being charged below zero C is a given.
    If that has damaged my battery, it should be a warranty issue.

    My Gen 3 plug-in spent 12 winters outside, and the battery had no degradation issues. Why should the Gen 5 battery be damaged from low temperatures? They both use a lithium battery. I guess I'll have to wait and see.
     
    #146 Paul Gregory, Feb 20, 2025 at 9:26 AM
    Last edited: Feb 20, 2025 at 9:34 AM
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  7. Bill Norton

    Bill Norton Senior Member

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    I am interested in a Gen5 Prime but posts like these have me thinking....
    Of course this simple resistive strip Battery Pack heating should start as soon as the pack gets too cold.
    Not sure what they are saying about '3 days'. TMS should be working anytime it's plugged in.

    And what if I get back from a 32 day vaca and my pack is now at a lovely -7°F, even though it's been plugged in the whole time? I like the mention of 'ignoring schedule settings.'
    When it's cold like this you want the pack in a happy temp range. Period.
    Why are you seeing msgs about the Thermal Management System doing -- what it's designed to do?
    Just keep the pack temp happy, Mkay? (let's not talk about how it does this when it's 107°F.)

    And then all this talk of the 12V battery dying, multiple times from many posters here, on a 1 yr old car.
    What's so hard about having the SW keep the 12V charged while plugged in?

    I guess I'll wait and see also....:whistle:
    What is the deal with toyota figuring out how to make a PHEV behave properly? Especially when it sounds like it's all SW.
    I had a Volt. I know it can be done....:unsure:

    The reason I'm looking into a new car is because I'm getting the first signs of the Chronic Head Gasket failure with my '10 Gen3 @167k miles.
    Do I sell it (as is. Buyer beware. Don't buy used cars from me...:cool: ) and buy an expensive newer PHEV?
    Or do I have Gasket Masters quickly replace the head gasket with an american Felpro head gasket and drive it another few 100k miles?(y)
     
  8. Paul Gregory

    Paul Gregory Active Member

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    I wouldn't try to hide any issues from the buyer. That'll come back to bite you.
     
  9. Bill Norton

    Bill Norton Senior Member

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    Really? Like karma? :whistle:

    Isn't it in the constitution, or somewhere, that clearly states that in America: Buyer beware. ?:rolleyes:

    I've sold two other Gen3's. One with THE head gasket failure starting.
    I did not have a laundry list of:
    All the bad things about the car I'm trying to sell. I only stated the good things. Just like any new or used car wranglers do.:whistle:

    Maybe karma only works if you believe in such things....:cool:

    Do you know how great the Advanced Technology Package works on Level 5 Prii that have that expensive option?
    Let's go for a little test drive and I'll show you!(y)
    I'm may be selling the '10 with that option.
    It worked even better on the '11 I sold that may or may not have had the Chronic Head Gasket failure.
    Is that my problem or Toyota's for engineering that allowed that problem to be in their Gen3's for 5 years?
     
  10. Paul Gregory

    Paul Gregory Active Member

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    If it weren't for the good people holding things together, it wouldn't be a world worth living in.
     
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  11. Bill Norton

    Bill Norton Senior Member

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    You, sir, sound like a good person.(y)
    I would buy a used car from you!:)

    World, beware of buying used cars. You never know.... Hence: Buyer Beware.
    A world worth living in depends on it!

    (Where did this saying originate?)

    edit: Canada !! You're all good people up there! I might join you someday, but I hate cold weather.
     
  12. Mendel Leisk

    Mendel Leisk Senior Member

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    West coast then. I'd probably shatter, on the prairies...
     
  13. Gokhan

    Gokhan Senior Member

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    It does not matter, and this is no-brainer. Get a Noco Genius (or similar smart battery maintainer) and leave it connected to the 12-V battery if the car is left undriven for more than a few days—with or without the traction battery connected to the charger. You also need to do this with the non-plugin Prius and in any kind of climate. Otherwise, your battery will keep dying. Also, connect a Noco Genius right away because currently, your 12-V battery is at a low SOC because of the previous drain occasions.
     
  14. Gokhan

    Gokhan Senior Member

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    There is really no issue with Gen 5 unless you drain the 12-V battery by not doing long trips at least every other day or so. If you do not, then, get a Noco Genius (or similar smart battery maintainer) and hook it up when needed (car not seeing regular long trips). Also, hooking up a Noco Genius should be the first thing you should do when you buy the car and bring it home because these cars often come with an already-drained battery from the dealer, and the 12-V charging system will not satisfactorily recharge them. So, it will be more than fine if you follow these precautions.
     
  15. Paul Gregory

    Paul Gregory Active Member

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    I always had a bit of antipathy towards those who say, "It's OK if everyone else is doing it."
     
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  16. Mendel Leisk

    Mendel Leisk Senior Member

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    It’s a little disconcerting, if high phantom load demands and anemic batteries have some doing superfluous driving.

    we’re now doing maybe 3k kms a year, garage parked, and the 12 volt constantly on a charger in the down times, the last battery I put in September 2015.
     
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  17. Gokhan

    Gokhan Senior Member

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    This is not really a Gen 4/Gen 5 Prius problem. With any modern car with a plethora of electronics, the parasitic drain will be high.

    I estimated it in my Gen 4 Prius Prime to be around a 2.5% SOC a day. It will add up quickly. With a flooded cell (I have an AGM cell), you get a higher self-drain on top of that. Moreover, if you don’t drive the car in long trips regularly, the SOC will never replenish. It takes about 40 minutes of driving to put about a 15% SOC—if the battery-management system (BMS) decides to do so. Another complication is that the Gen 4/Gen 5 BMS likes to deliberately drain a charged battery when you drive the car (instead of recharging it) because it likes to keep the SOC at 75–85% (instead of the ideal 100% for a lead–acid cell) to “improve the fuel economy.” And if you keep leaving the car undriven or have other drain events, you will end up with a dead battery in no time.

    Again, this is a no-brainer—get a Noco Genius (or similar smart battery maintainer), and use it (1) as soon as you buy the car (as it will more than likely come with a very low SOC from the dealer), (2) if you don’t drive the car in long trips regularly, and (3) every few months to fully recharge the battery.
     
    #157 Gokhan, Feb 20, 2025 at 5:40 PM
    Last edited: Feb 21, 2025 at 1:15 AM
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  18. bob12345

    bob12345 New Member

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    So those who live in apartments should not purchase a 5th gen Prius? I find a hard time to accept that.
    I will report here if I have any starting issues since I have zero plans to use a battery maintenance. I drive mine daily expect maybe one day a week where the vehicle sits outside and business trips through the year when the vehicle isn't started for 4 - 7 days.
    My summary is:
    Owners shouls read and follow the Owners Manual per standard process. Any vehicle starting issues or anyother issues dor that matters should be reported to there local dealer.
     
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  19. Paul Gregory

    Paul Gregory Active Member

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    Some people just live to dump on someone by criticizing them for having an issue.
    I call them "trolls" because they just want to fight with someone.
    I am currently doing a battery voltage test, by leaving my car parked without the maintainer plugged in. I plan to note the voltage drop over time. I could do a current test, but I have found it to be variable, and requires more active participation on my part. I can't do anything about the parasitic drain anyway, but knowing about the voltage drop is more useful.
     
  20. Mendel Leisk

    Mendel Leisk Senior Member

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    You lost me there; is that your category for me?